JPH03214719A - Manufacture of chip-type solid electrolytic capacitor - Google Patents

Abstract

PURPOSE:To prevent deterioration of characteristics by filling a thermosetting resin liquid and then curing it for forming a resin-armored body after placing a capacitor element within a recessed part of a formed mold. CONSTITUTION:An anode lead wire 2 for external lead-out is welded to an anode lead 1a of a capacitor element 1 having a solid electrolyte consisting of a conductive macromolecular and then a cathode lead wire 3 for external lead-out is attached to a cathode surface 1b through a conductive adhesion material 4. Then, the capacitor element 1 is placed within a recessed part 5a for a mold where the upper surface is open, a thermosetting synthetic resin liquid 6a is filled into the recessed part 5a, it is hardened for forming a resin- armored body around the capacitor element 1, and then an anode lead wire 2 and a cathode lead wire 3 are bent in a specified direction along the surface of the resin-armored body. As a result, nearly no mechanical stress is applied to the solid electrolyte when forming the resin-armored body and neither an expensive molding machine nor a forming mold is needed, thus preventing faulty characteristics and reducing cost.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing a chip-type solid electrolytic capacitor having a solid electrolyte made of a conductive polymer.

[Conventional technology]

When a conductive polymer is used as the solid electrolyte, a capacitor element consisting of a coil of valve metal foil, such as aluminum, is immersed in a monomer such as pyrrole, and then electrically or chemically polymerized. Polypyrrole (fi electrolyte) is formed between the aluminum foils. When making a chip, an anode lead wire for external extraction is welded to the anode lead of this capacitor element, and
A cathode lead wire for external extraction is attached to the cathode surface via a conductive adhesive, the capacitor element is placed in the cavity of a molding die, and a resin exterior body is formed by, for example, transfer molding. The lead wire is bent in a predetermined direction along the surface of the resin sheath.

[Problem to be solved by the invention]

Chip-type solid electrolytic capacitors are manufactured in the manner described above, but this method has the following drawbacks.

That is, since the solid electrolyte made of a conductive polymer is susceptible to mechanical stress, the pressure during molding of the resin exterior body may cause it to peel off from the metal foil or the like, resulting in deterioration of characteristics.

Furthermore, since the molding machine and its molding die are expensive, an increase in cost is unavoidable.

[Means to solve the problem]

This invention was made to solve the above-mentioned conventional problems, and its structural feature is that an anode lead wire for external extraction is welded to an anode lead of a capacitor element having a solid electrolyte made of a conductive polymer. At the same time, a cathode lead wire for external extraction is attached to the cathode surface via a conductive adhesive, and then the capacitor element is placed in a molding recess with an open top surface, and a thermosetting material is placed in the recess. -3- Fill with a synthetic resin liquid and solidify it to form a resin sheath around the capacitor element, and connect the anode lead wire and the cathode lead wire in a predetermined direction along the surface of the resin sheath. It's about bending it.

Note that the molding recess may be filled with a thermosetting synthetic resin liquid first, and the capacitor element may be immersed therein.

[For production]

According to the above method, almost no mechanical stress is applied to the solid electrolyte made of a conductive polymer during molding of the resin exterior body. Moreover, since no expensive molding machine or mold is required, costs can be reduced by that much.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

In FIG. 1, numeral 1 represents a capacitor element that is made into a chip according to the present invention. According to this embodiment, the capacitor element 1 is made of a foil-wound body using a conductive polymer as a solid electrolyte. That is, an anodized film is formed on an etched electrode foil made of a valve metal foil such as aluminum in an aqueous solution containing adipic acid, and then cut into a predetermined length. After attaching the anode lead 1a to this electrode foil, separators are stacked on top of each other and wound to a predetermined diameter. Next, 200-4
After carbonizing the separator at 00°C, reconstitution is performed with an aqueous ammonium adibate solution. Next, conductive polymer (
For example, after immersing in an aqueous solution of monomer (pyrrole),
Immerse it in an oxidizing agent containing ammonia persulfate for a specified period of time,
Forms a solid electrolyte of conductive polymer. Thereafter, it is immersed in an aqueous solution containing a conductive heptomer, toluenesulfonic acid, etc., and electrochemically polymerized to form a polymer (for example, polyvirol) with excellent conductivity. Note that a cathode surface 1b made of, for example, silver paste is provided on the solid electrolyte thus formed.

Prior to forming the resin exterior body, an anode lead wire 2 for external extraction is welded to the anode lead 1a, and a cathode lead wire 3 for external extraction is welded to the cathode surface 1b with a conductive adhesive such as silver. Attached via 4. In this case, both the anode lead wire 2 and the cathode lead wire 3 are bent into a crank shape so that their respective tips 2a and 3a are aligned substantially on the same plane, and the capacitor element 1 is formed as shown in FIG. The mold 5 is supported by each tip 2a, 3a.
It is arranged so as to float in the recess 5a. The mold 5 is preferably made of an epoxy mold release material such as silicone, but may be a mold used for transfer molding or the like.

Thereafter, a thermosetting resin liquid, for example, an epoxy resin liquid 6a, is filled in the recess 5a, and is taken out after it solidifies. In this way, the resin sheath 6 is formed around the capacitor element 1, as shown in FIG. In this case, in the figure, the top surface of the resin sheathing body 6 becomes the bottom surface facing the mounting surface of the circuit board, and in this example, the tips 2a and 3a of the anode lead wire 2 and the cathode lead wire 3 are connected from the bottom surface of the resin sheathing body 6. 6 is bent into a substantially L-shape along each side surface to form a chip component.

Note that, unlike the above embodiment, the recess 5a may be filled with a thermosetting resin liquid first, and the capacitor element 1 may be immersed therein. Further, this invention is not limited to the foil-wound type capacitor element of the above embodiment, but can also be applied to a capacitor element made of a sintered body of valve metal powder.

〔Effect of the invention〕

As explained above, according to the present invention, after the capacitor element is placed in the recess of the mold, the thermosetting resin liquid is filled, or the recess is first filled with the thermosetting resin liquid. By immersing the capacitor element in the liquid and curing the resin liquid to form the resin exterior body, almost no mechanical stress is applied to the solid electrolyte made of conductive polymer during molding of the resin exterior body. Therefore, characteristic defects can be prevented. Furthermore, since expensive molding machines and molds are not required, costs can be reduced accordingly.

[Brief explanation of drawings]

FIG. 1 is a -7- explanatory diagram for explaining the manufacturing method of the present invention, and FIG. 2 is a side view showing an example of a solid electrolytic capacitor formed into a chip according to the present invention. In the figure, 1 is a capacitor element, 1a is an anode lead, 1b is a cathode surface, 2 is an anode lead wire, 3 is a cathode lead wire, 4 is a conductive adhesive, 5 is a mold, 5a is a recess, 6 is a resin exterior It is the body.

Claims (2)

[Claims] (1) An anode lead wire for external extraction is welded to the anode lead of a capacitor element having a solid electrolyte made of a conductive polymer, and a cathode lead wire for external extraction is welded to the cathode surface via a conductive adhesive. After mounting, place the capacitor element in a molding recess with an open top surface,
A thermosetting synthetic resin liquid is filled in the recess and solidified to form a resin sheath around the capacitor element, and the anode lead wire and the cathode lead wire are connected along the surface of the resin sheath. A method for manufacturing a chip-type solid electrolytic capacitor, characterized in that the capacitor is bent in a predetermined direction. (2) The chip according to claim 1, wherein after filling the recess with a thermosetting synthetic resin liquid, the capacitor element is immersed in the resin liquid to form a resin exterior body around the capacitor element. A manufacturing method for type solid electrolytic capacitors.